Onyx is an opaque and semi-opaque variety of Chalcedony with a strong sheen. Loved by the Ancient Romans, this gemstone often displays marvelous multicolored bands.


Its name derives from the Greek ‘Onyx’, meaning ‘nail’ or ‘claw’.

Onyx extraction

Onyx is extracted in Brazil, India, Madagascar and Uruguay.

Two examples of Onyx with white striations

Two examples of Onyx with white striations

The history of Onyx

A black Agate with a cabochon cut

A black Agate with a cabochon cut

According to legend, this gemstone was created when Cupid trimmed the fingernails of a sleeping Venus and left them lying on the floor. As the parts of a divine creature are not mortal, the Gods transformed them into gemstones, which became known as Onyx.

In Ancient Greece, all colors of Chalcedony were called ‘Onyx.' Later, the Romans used this name to describe only those Chalcedony gemstones with black and dark brown colors.

Like Agate, Onyx is a striated gemstone. In Ancient Rome, it was used for glyptics - a type of carving where the various striations in color are used to darken the relief sections, yielding wonderful engravings. Using this technique, the Romans produced cameos with images of people or famous scenes.

The red-brown variety with white bands is called ‘Sardonyx.' In Ancient Rome, it was highly valued as a seal, as it did not adhere to wax.

Onyx was often associated with instinct and intuition. It was believed to help develop authority and analytical thought.

Properties of Onyx

Onyx is usually considered a black gemstone, but in reality, being a variety of Agate, it presents white striations. Onyx is an opaque gemstone varying from dark brown to black in color.

An agate with colored bands

An Agate with colored bands

Care for Onyx

Onyx may be subjected to normal cleaning, including steam or ultrasound cleaning.

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